1. Field of the Invention
The invention in general relates to microwave signal processing, and particularly to a two port magnetostatic wave device.
2. Description of the Prior Art
In the microwave signal processing field, circuits or devices which increase the signal to noise ratio are key components in such circuitry as frequency memory loops which are important in electronic countermeasure systems.
A memory loop generally consists of an amplifier having feedback through a delay line with conditions being such that the loop will oscillate and produce a CW output signal in response to an input pulse signal. If the input frequency signal includes noise, the amplifier not only amplifies the signal but also amplifies this noise which results in a reduction in the maximum storage time of the loop and in a degraded, and sometimes unusable output signal. To avoid this, signal-to-noise enhancers are utilized and may include ferrite reflectors in conjunction with circulators and matching circuitry. Many such enhancers have limited bandwidth capabilities.
The present invention provides for a signal to noise enhancer which is of extremely simple construction and achieves broad bandwidth operation utilizing gyromagnetic materials such as a ferrite. By way of example such devices find use in the microwave signal processing art as two port non-reciprocal attenuators or two port attenuators, the attenuation of which is variable in accordance with a variable applied magnetic bias field. Such attenuators, however, would not function to increase the signal to noise ratio if utilized, for example in a frequency memory loop.